A novel lighting assembly that incorporates a high brightness light emitting diode (LED) in a compact assembly for further integration into a lighting device is provided. The lighting head assembly of the present invention provides several novel aspects that are all closely integrated to provide a unique assembly for incorporating a high brightness LED into a lighting device. In particular, the head assembly utilizes a receiver sleeve that includes a non reflective coating to provide a high level of contrast between the lighting element and the interior region surrounding the lighting element. Further, an optical element is coupled to the receiver to capture an image of the lighting element to provide a sharp, uniformly illuminated image in the far field of the device.
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1. A lighting head assembly comprising:
a receiver sleeve having a first end and a second end, a tubular side wall having an interior surface, said tubular side wall extending between said first and second ends and a substantially planar end wall at said first end, said end wall having an interior surface, an exterior surface and an aperture in said end wall;
a non-reflective coating on said interior surfaces of said side wall and said end wall; and
a lighting element having an optical end, said optical end of said lighting element received on the exterior of said receiver sleeve in alignment with said aperture adjacent said exterior surface of said end wall, wherein said optical end of said lighting element is substantially entirely on the exterior side of the plane of said end wall, wherein light output from said lighting element is directed into said aperture.
11. A lighting assembly comprising:
a receiver sleeve having a first end, a second end and an interior surface,
an end wall at said first end of said receiver sleeve, said end wall having an interior surface, an exterior surface and an aperture therein;
a lighting element having an optical end, said optical end of said lighting element received on the exterior of said receiver sleeve in alignment with said aperture adjacent said exterior surface of said end wall, wherein light output from said lighting element passes through said aperture, illuminating said aperture such that the light entering the receiver sleeve through the illuminated aperture does not impInge on the interior surface of said end wall, said interior surface of said end wall remaining non-illuminated; and
a lens adjacent said second end of said receiver sleeve, wherein said lens captures and projects a circular image of the illuminated aperture and said non-illuminated end wall forming a clearly defined beam cut-off edge thus providing a circular illuminated spot having a clearly defined edge in the far field of said lighting assembly.
17. A flashlight assembly comprising:
a housing having a first end and a second end;
a receiver sleeve received into said first end of said housing, said receiver sleeve having a first end, a second end, an interior surface and an end wall at said first end of said receiver sleeve, said end wall having an interior surface, an exterior surface and an aperture therein;
a mounting board adjacent said exterior surface of said end wall of said receiver sleeve, said mounting board having first and second electrical contacts thereon;
a power source received in said second end of said housing, said power source in electrical communication with said first and second electrical contacts on said mounting board;
a lighting element having an optical end and first and second contact leads extending therefrom, said lighting element mounted to said mounting board such that said first and second contact leads are in electrical communication with said first and second electrical contacts respectively, said optical end of said lighting element being on the exterior of said receiver sleeve in alignment with said aperture adjacent said exterior surface of said end wall, wherein light output from said lighting element passes through said aperture illuminating said aperture such that the light entering the receiver sleeve through the illuminated aperture does not impinge on the interior surface of said end wall, said interior surface of said end wall remaining non-illuminated;
switching means to selectively energize said lighting element; and
a lens adjacent said second end of said receiver sleeve, wherein said lens captures and projects a circular image of the illuminated aperture and said non-illuminated end wall forming a clearly defined beam cut-off edge thus providing a circular illuminated spot having a clearly defined edge in the far field of said flashlight.
2. The lighting head assembly of
3. The lighting head assembly of
5. The lighting head assembly of
6. The lighting head assembly of
a lens adjacent said second end of said receiver sleeve, whereby said lens captures a circular image of the light output in said aperture and said interior surface of said end wall and projects said circular image into the far field of said lighting assembly thus providing a circular illuminated spot having a clearly defined edge.
7. The lighting head assembly of
8. The lighting head assembly of
a tubular tail portion extending from said exterior side of said end wall concentric to said aperture, said optical end of said lighting element received in said tail portion, wherein said output end of said lighting element is substantially entirely on the exterior side of the plane of said end wall, wherein light output from said lighting element is directed into said aperture.
9. The lighting head assembly of
a lens adjacent said second end of said receiver sleeve, whereby said lens captures a circular image of the light output in said aperture and said interior surface of said end wall and projects said circular image into the far field of said lighting assembly thus providing a circular illuminated spot having a clearly defined edge.
10. The lighting head assembly of
12. The lighting assembly of
a tubular tail portion extending from said exterior surface of said end wall concentric to said aperture, said optical end of said lighting element received in said tail portion, wherein said output end of said lighting element is substantially entirely on the exterior side of the plane of said end wall, wherein light output from said lighting element is directed into said aperture.
13. The lighting assembly of
a non-reflective coating on said interior surfaces of said receiver sleeve and said end wall.
15. The lighting assembly of
18. The flashlight of
a tubular tail portion extending from said exterior surface of said end wall concentric to said aperture, said optical end of said lighting element received in said tail portion, wherein said output end of said lighting element is substantially entirely on the exterior side of the plane of said end wall, wherein light output from said lighting element is directed into said aperture.
19. The flashlight of
a non-reflective coating on said interior surfaces of said receiver sleeve and said end wall.
21. The flashlight of
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This application is related to and claims priority from earlier filed provisional patent application No. 60/437,810, filed Jan. 3, 2003.
The present invention relates to a new lighting head assembly for use in lighting devices such as commercial and residential lighting fixtures, flashlights and miniature flashlights. More particularly, the present invention relates to compact and efficient lighting head assemblies for use with lighting devices of the type employing a high brightness light emitting diode (LED) to provide a smooth uniform spotlight beam having sharp edges.
Most commercially available lighting devices are designed to provide an on-axis, high intensity peak in their beam distribution as is typically found in flashlights with smooth reflectors or specialty architectural spotlights such as picture lights. In other words, most conventional lighting assemblies provide a central spot that is highly illuminated with a surrounding beam fall off region that varies from assembly to assembly. In general, these smooth reflector type assemblies simply re-image the light source into the far field of the device and create a poorly distributed, non-uniform illuminated field. Attempts to provide a more uniform beam distribution include the use of multi-faceted reflectors, however, the resulting beam pattern tends to be Gaussian with no sharp edge definition between the area illuminated by the beam and the surrounding non-illuminated area. In both the faceted and smooth reflector cases, the reflector generally tends to be parabolic in shape. While this shape reduces the direct re-imaging of the light source, this solution simply smears the image taken from the far field of the light source and projects that smeared image in the far field of the flashlight beam thereby still providing a non-uniform light image in the far field of the lighting device.
Other prior art attempts to produce a focused light source include the provision of a standard convex lens with a relatively long convergence factor in front of an LED package. These devices also produce an unacceptable result as they capture the far field image from a plane projected in front of the LED package and simply enlarge the LED image and then reflects that image in a reversed pattern in the flashlight beam far field. If the beam pattern is carefully studied, an image of the emitter die, diode and reflector cup can easily be identified in the beam image.
In most of the prior art assemblies, in order to provide even the marginally acceptable results using the assemblies described above, the lighting device needed a large reflector and a relatively large lens with a long focal length. These components dictated that the head of the light assembly have a large dimension as well. Further, because the LED lighting elements generate a great deal of heat, a heat dissipation path must be provided as well. In general, this heat dissipation path is simply provided in the form of creating a large volume of air space around the LED. All of these factors combined in the prior art to prevent the design of a compact lighting assembly that could incorporate a single high brightness LED.
Finally, in order to manufacture a portable lighting assembly that is compact it is desirable to provide a lighting assembly that can be operated using a single conventional battery such as a conventional AA or AAA cell battery. However, in order for this type battery to activate the LED, step up circuitry must be provided to increase the 1.5 volt battery output to at least the threshold voltage required to illuminate the LED. The drawback is that this circuitry is extremely sensitive to reversed polarity. Therefore there is also a need for providing reliable polarity protection thereby preventing a user from accidentally activating the lighting assembly with a battery that has been installed in reverse orientation.
Therefore, there is a need for a lighting device that produces a smooth, evenly distributed beam of light. In addition, there is a need for a lighting device that provides a high intensity beam of light that has a homogeneous illumination pattern. There is also a need for a high intensity flashlight beam that provides a uniform field of illumination and that has a sharp edge between the illuminated field and the non-illuminated field. There is a further need for a lighting head assembly that is compact and efficient in size while providing an integrated heat dissipation pathway. There is yet a further need for a compact lighting assembly that includes reliable and integrated polarity protection for the control circuitry therein.
In this regard, the present invention provides a novel lighting assembly that incorporates a high brightness light emitting diode (LED) in a compact assembly for further integration into a lighting device. The lighting head assembly of the present invention provides several novel aspects that are all closely integrated in a single compact assembly to provide a solution to the drawbacks identified in the prior art. The lighting head assembly of the present invention is suitable for incorporation into any type of lighting device such as architectural lighting, accent lighting, task lighting and flashlights. The preferred embodiment shown and described in the disclosure of the present invention is designed for incorporation into a flashlight device. In this regard, the present invention will be described in the context of a flashlight assembly although the same concepts disclosed with respect to the preferred embodiment are also suitable for use in any type of lighting assembly.
The central element of the assembly of the present invention is a tubular receiver sleeve that is configured to receive the lighting element in a manner that supports and aligns the lighting element along an optical axis. The receiver serves both to contain and to channel the light from the LED and direct it forwardly along the optical axis. To aid in channeling of the light, the reciever includes a narrowed tail section that entirely surrounds the side portions of the optical element of the LED. By providing a narrowed tail element that surrounds the LED, the receiver also provides an efficient structure for capturing the heat generated by the LED element and directing that heat away from the LED.
In the preferred embodiment, the present invention utilizes a single high brightness lighting element such as an LED that is mounted onto a circuit board and placed into the tail of the receiver. When the LED is placed into the tail element of the receiver, the optical axis of the LED is automatically centered along the central axis of the receiver. In this manner the ability to further incorporate the assembly into lighting devices, such as flashlights, is greatly enhanced while providing the ability to utilize additional beam control elements in a precise and controlled manner. The end of the receiver opposite the tail element is configured to receive optical control elements such as a lens or an optical zoom assembly to capture the light output of the LED and project it into the far field of the device in a uniformly illuminated and carefully controlled beam.
An additional feature that is incorporated into the receiver to facilitate the compact nature of the present assembly is the provision of an electrically conductive pathway for connecting one terminal of the battery to the LED driver circuitry. By using the receiver to provide this conductive pathway, the need for additional connections or wire bonds between the driver circuitry for the LED and the housing is eliminated. In this manner, the assembly process is streamlined and the precision of the finished device is greatly improved.
In an effort to maintain the compact nature of the present invention, it is also desirable to drive the LED using a conventional single cell battery such as an AA or AAA type battery. As can be appreciated, this type battery is a 1.5 volt power source. Since typical LED's require 3.0 volts for operation, a step up circuit is provided in the LED driver circuitry. Step up circuits of this type are particularly sensitive and are susceptible to damage resulting from reversed polarity DC current. The present invention therefore also includes a novel construction for insuring that contact to the power source will only occur if the battery is installed in the proper orientation.
Accordingly, one of the objects of the present invention is the provision of a compact lighting assembly that includes a high intensity light source such as an LED. Another object of the present invention is the provision of a lighting assembly that utilizes a receiver sleeve to position an LED along the optical axis of the lighting device thereby offering improved light capture and transfer. A further object of the present invention is the provision of a lighting assembly that utilizes a receiver sleeve to both center the LED light source along the optical axis of the assembly and act as a heat sink to transfer the heat generated by the LED away from the LED and the driver circuitry. Yet a further object of the present invention is to provide a compact LED lighting assembly that utilizes a receiver to center the LED, act as a heat sink for the LED and to provide an electrically conductive path from one terminal of the battery to the LED driver circuitry. An even further object of the present invention is the provision of a compact lighting assembly that includes integrated voltage polarity protection for the LED driver circuitry.
Other objects, features and advantages of the invention shall become apparent as the description thereof proceeds when considered in connection with the accompanying illustrative drawings.
In the drawings which illustrate the best mode presently contemplated for carrying out the present invention:
Referring now to the drawings, the lighting head assembly of the present invention is shown and illustrated in the form of a compact flashlight that is generally illustrated and indicated at 10 in
Turning now to
The receiver sleeve 20 is preferably both electrically and thermally conductive. In the preferred embodiment, the receiver sleeve 20 is formed from brass or aluminum thereby making the sleeve 20 highly thermally and electrically conductive. Alternative materials such as filled conductive polymers or other metals may also be suitable for forming the receiver sleeve 20 provided that the material is sufficiently thermally and electrically conductive to maintain the functionality of the lighting head assembly 14.
The tail portion 24 of the receiver sleeve 20 has a diameter that is smaller than the overall diameter of the receiver sleeve 20. Further, the tail portion 24 has a diameter that slightly larger than the outer diameter of the lighting element 30. In this manner the lighting element 30 is received into the tail portion 24 and retained in a position that centers the lighting element 30 in the aperture 26 in the rear wall 22 of the receiver sleeve 20 and places the optical axis of the lighting element 30 into alignment with the central axis 28 of the receiver sleeve 20.
The lighting element 30 is preferably an LED although a conventional filament lamp or xenon lamp could also be used in the present invention. The LED 30 has an optical head portion 32 with two leads 34, 36 extending therefrom. The LED 30 is mounted onto a mounting board 38 wherein one of the contact leads 34 is in electrical communication with an electrical contact pad 40 formed on the top surface thereof. The electrical contact pad 40 is formed in concentric relation to the position where the lighting element 30 is mounted. As can be seen, when the lighting element 30 is received into the tail portion 24 of the receiver sleeve 20, the tail portion 24 is in contact with the contact pad 40 formed on the top surface of the mounting board 38. In this manner, an electrically conductive path is formed from the body of the receiver 20 through the tail piece 24, into the contact pad 40 on the mounting board 38 and directly to one of the contact leads 34 of the lighting element 30. This electrically conductive pathway facilitates electrical connection to the lighting element 30 on the mounting board 38 with out the need to include additional wire bonds or spring. Further, assembly steps where soldered connections need to be completed are eliminated. In this manner, the complexity of the assembly is greatly reduced while a more reliable and durable assembly is formed.
This direct conductivity pathway between the lead 34 of the lighting element 30 and the receiver sleeve 20 also serves the secondary purpose by providing a thermally conductive pathway to dissipate heat from the lighting element 30. As is well known in the art most of the heat generated by an LED device 30 is transmitted back through the contact leads 34, 36. In the present invention this heat is conducted down the lead 34, through the contact 40 on the mounting board 38 and transmitted into the receiver sleeve 20. Since the receiver 20 has a large thermal mass, it serves as a heat sink for absorbing and further dissipating the heat generated by the lighting element 30. Additionally, since the walls of the tail portion 24 of the receiver 20 are in close proximity to the optical portion 32 of the lighting element 30, heat that is radiated by the lighting element 30 is also absorbed by the walls of the tail portion 24 and further dissipated by the receiver sleeve 20. When the lighting head assembly 14 of the present invention is fully implemented by installing the assembly 14 into the housing 12, the outer wall of the receiver sleeve 20 is in electrical and thermal contact with the inner surface of the outer housing 12. In this manner, the housing 12 provides additional thermal mass for dissipation of the waste heat generated by the lighting element 30 while also extending the electrically conductive pathway for one contact of the power source 16 to be connected to the contact 40 on the top surface of the mounting board 38 and ultimately to the contact lead 34 of the lighting element 30.
The lighting head assembly 14 may also include driver and control circuitry 42 that is mounted onto the mounting board 38. Preferably, the control circuitry 42 is electrically connected between the second contact lead 36 of the lighting element 30 and a contact pad 44 formed on the bottom surface of the mounting board 38. The circuitry 42 is placed in contact with the second lead 36 and the bottom contact 44 so that it is not deposed along the thermal dissipation pathway that is provided between the lighting element 30 and the receiver sleeve 20. Further the circuitry 42 is located on the mounting board 38 in a position that is outside of the tail portion 24 of the receiver sleeve 20. In this manner, the circuitry 42 is shielded from damage that may result from being exposed to the heat generated by the lighting element 30.
A spring 46 is installed adjacent the bottom of the mounting board 38 and is in electrical communication with the contact pad 44 on the bottom surface thereof. The spring 46 provides an electrically conductive pathway to facilitate a connection with the second electrical contact of the power source 16. The spring 46 engages a metallic contact cap 48 that is formed within an outer nonconductive plunger 50. The plunger 50 includes an aperture 52 in the center of the bottom surface thereof. The aperture 52 is formed to have a dimension that allows the smaller contact end 54 of the power source 16 to pass through the aperture 52 and contact the contact cap 48 while preventing the larger contact end 56 of the power source 16 from reaching the contact cap 48 should the power source 16 be installed in reverse orientation. Specifically, the aperture 52 in the plunger 50 is sized to allow the smaller positive terminal 54 of an AA or AAA battery 16 to extend through the aperture 52 and contact the contact cap 48 while preventing the negative terminal 56 from reaching the contact cap 48. This polarity protection is necessary to protect the control circuitry 42 on the mounting board 38 from damage as a result of being exposed to reverse polarity. This is particularly necessary in applications where an LED lighting element 30 is used in conjunction with a single conventional cell battery 16 having a 1.5 volt supply voltage. Since the threshold voltage required for activation of an LED 30 is typically greater than the 1.5 volts available in an AA or AAA battery 16, the control circuitry 42 must include a step up circuit. Since step up circuits are highly sensitive to damage resulting from reverse polarity, a permanent means for protecting the lighting head assembly 14 from having reverse polarity applied is necessary. In this manner the plunger 50 arrangement provides the necessary protection while also facilitating electrical connectivity with the second contact 44 on the mounting board 38.
The spring 46, while providing spring force for the plunger 50 and contact cap 48 also urges the mounting board 38 forward against the end of the tail portion 24 of the receiver sleeve 20. In this manner, the spring 46 serves to maintain the mounting board 38 and the electrical contact 40 on the top surface thereof tightly against the tail portion 24. The forward pressure of the spring 46 is an important feature in the head assembly 14 because the mounting board 38 is formed to have a diameter that is smaller than the inner diameter of the outer housing 12. This allows the mounting board 38 to float slightly in a laterally un-restrained manner during assembly as the lighting element 30 is inserted into the tail section 24 and the head assembly 14 is installed into the end of the outer housing 12. When fully assembled, the slight degree of freedom of the mounting board 38 allows the lighting element 30 to be captured and centered in the aperture 26 of the receiver sleeve 20 and facilitates alignment of the entire assembly.
To complete the flashlight assembly 10, an end cap assembly 18 is provided to retain the battery 16 within the outer housing 12 and further provide a means for selectively activating the flashlight 10. The cap 18 includes an actuator 58 with a contact plate 60 on the inner surface thereof. The actuator 58 is depressed by the user causing the contact plate 60 to form an electrical connection between the negative terminal 56 of the battery 16 and the end of the outer housing 12 thereby completing the electrical circuit and energizing the lighting element 30. When the actuator 58 is released the spring 46 in the plunger 50 presses the battery 16, contact plate 60 and actuator 58 rearwardly opening the circuit. Additionally, the end cap 18 can be fully tightened to retain the contact plate 60 into the closed position providing a constant “on” function.
Finally, to create a waterproof assembly an assortment of gaskets and O-rings are also provided. As can be seen in
Turning now to
Turning to
It can therefore be seen that the present invention provides a novel and compact lighting head assembly 14 that provides a high quality illumination while being efficient and easy to assemble. The lighting head assembly 14 includes a novel receiver sleeve 20 that serves to remove waste heat from the device, facilitate electrical connections and control the light output. Further, the lighting head assembly 14 is compact and easily modified to allow its incorporation into a variety of different lighting devices to provide a well defined, highly controlled, high intensity beam output thereby creating a useful and novel assembly. For these reasons, the instant invention is believed to represent a significant advancement in the art, which has substantial commercial merit.
While there is shown and described herein certain specific structure embodying the invention, it will be manifest to those skilled in the art that various modifications and rearrangements of the parts may be made without departing from the spirit and scope of the underlying inventive concept and that the same is not limited to the particular forms herein shown and described except insofar as indicated by the scope of the appended claims.
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